Nature has secreted many of her most useful treasures in most forbidding places. The nitrates which fertilize so much of Europe are drawn from the fiercest of South American deserts, and the gold which measures American commerce is mined in the arctic wilds of Alaska or in the almost inaccessible scarps of the western highlands. The description of these regions and the portrayal of their relation to the rest of the world is the purpose of Part I of this book.